Ferrari had contacted Formula One's governing body, the FIA, concerning the move by the Red Bull driver during last weekend's season-ending Brazilian Grand Prix that won him a third successive title.

There had been speculation that the manoeuvre could have been illegal and, if so, Vettel could have been sanctioned and thereby stripped of his title in favour of Ferrari's Fernando Alonso who missed out on the championship by just three points.

But Formula One ringmaster Ecclestone said it was a shame that the climax to the season had been overshadowed by the row.

"It's a shame because everything had gone so well," he told the Daily Telegraph.

"It was a super race, a super championship. Now everyone is talking about this. The problem is that no-one knows what is going on."

On Thursday, the respected Autosport magazine said there was "no doubt" at the FIA that Vettel had overtaken legitimately on lap four of the race because a green flag had already been displayed in the yellow flag sector, allowing drivers to resume passing.

No team had asked for a review of the incident, it added.

"In the rules and regs normally you have to protest," added Ecclestone.

"They (Ferrari) missed that time. Then there is the fact that a green flag was shown, which nobody seems to dispute. It's a complete joke. What they are saying in that letter is wrong. I don't think there needs to be any action taken. It's completely and utterly wrong."

On Wednesday, footage emerged on YouTube which appeared to show Vettel, the youngest triple world champion in history, overtaking Toro Rosso's Jean-Eric Vergne under yellow flags.

Overtaking under caution is outlawed and is usually punished with a drive-through penalty.

But in cases where the infringement is not spotted, the sanction is a 20-second penalty handed out retrospectively.

Vettel was sixth in Sunday's rain-lashed race, while double world champion Alonso was second behind McLaren's Jenson Button.

Ferrari said they had wanted the FIA to clarify the rules.

"Ferrari asked, by means of a letter, for a clarification from FIA regarding VET's (Vettel's) overtaking move on VER (Vergne) during lap 4 of the Brazilian GP," the Italian team said on its Twitter account @insideferrari.

Vettel's victory had already been overshadowed by claims from Ferrari that Alonso should have been crowned champion.